共查询到20条相似文献,搜索用时 62 毫秒
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介绍应用CPU和现场可编程逻辑阵列(FPGA)/复杂可编程逻辑器件(CPLD)结合设计电子系统的优势.基于AT89C51单片机系统实现FLEK10K的在线可重配置(ICR),PC机和AT89C51串行通信实现在线升级,PC机下载配置实现在线调试.采用直接数字频率合成(DDS)技术,实现波形发生器.应用电子设计自动化(EDA)技术,以FPGA/CPLD器件为核心,采用FPGA设计的DDS不仅可方便地实现各种比较复杂的调频、调相和调幅功能,而且具有良好的实用性.文中给出了系统的工作原理和设计方法. 相似文献
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一种基于双C/S架构的视频监控系统 总被引:1,自引:0,他引:1
提出了一种集散武的视频监控系统,该系统采用双C/S架构,并由嵌入式视频采集终端、视频服务器和客户端3部分组成.目前,该系统已被用于网络实验室对实际实验设备的监控. 相似文献
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基于C/S结构的应用系统客户端和服务端之间的通信处理机制是C/S结构应用系统的重要组成部分.一直以来对于兼顾高速的服务端、友好的用户界面和跨平台的通信没有一个完美的解决方案.为了平衡这一矛盾,本文提出了一种新的通信处理机制.该机制使用不同的编程语言(C 和Java)制作客户端和服务端,采用自定义标注语言和XML相结合的纯字符流进行通信.较好地解决了基于C/S结构的应用系统跨平台跨编程语言快速通信处理的问题.实验结果表明该机制能有效地解决C/S结构应用系统跨平台的通信处理问题. 相似文献
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针对远程CPLD(复杂可编程逻辑器件)/FPGA(现场可编程门阵列)的新型配置需求,给出了基于TCP/IP远程配置的模型以及解决远程配置问题的算法,并应用VB语言实现了算法,经实际TCP/IP网络环境下运行验证,证明了算法的正确性和有效性. 相似文献
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针对高铁地震预警设计了一套基于C/S构架的六通道24 bit数据采集系统。系统硬件由控制板和可拆卸式多通道采集板组成。控制板由STM32F407单片机、SD存储卡和以太网接口组成,完成采集板控制,数据的读取、存储和传输功能;采集板由FPGA控制母版与6个独立的24 bit AD采集卡组成,完成六通道AD同步采样、数据打包和传输功能。服务器通过移植lwip,结合客户端Lab VIEW网络编程,完成了C/S构架软件系统设计,实现了数据远程参数设置和波形实时显示等功能。测试结果表明:采集系统通道一致性好,在200 sample/s采样率下每通道数据采集信噪比优于140dB。 相似文献
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Wei-Chou Hsu Dong-Hai Huang Yu-Shyan Lin Yeong-Jia Chen Jun-Chin Huang Chang-Luen Wu 《Electron Devices, IEEE Transactions on》2006,53(3):406-412
This paper proposes a In/sub 0.5/Al/sub 0.5/As/In/sub x/Ga/sub 1-x/As/In/sub 0.5/Al/sub 0.5/As (x=0.3-0.5-0.3) metamorphic high-electron mobility transistor with tensile-strained channel. The tensile-strained channel structure exhibits significant improvements in dc and RF characteristics, including extrinsic transconductance, current driving capability, thermal stability, unity-gain cutoff frequency, maximum oscillation frequency, output power, power gain, and power added efficiency. 相似文献
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《Electronics letters》1990,26(1):27-28
AlGaAs/GaInAs/GaAs pseudomorphic HEMTs with an InAs mole fraction as high as 35% in the channel has been successfully fabricated. The device exhibits a maximum extrinsic transconductance of 700 mS/mm. At 18 GHz, a minimum noise figure of 0.55 dB with 15.0 dB associated gain was measured. At 60 GHz, a minimum noise figure as low as 1.6 dB with 7.6 dB associated gain was also obtained. This is the best noise performance yet reported for GaAs-based HEMTs.<> 相似文献
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A 12 /spl times/ 12 In/sub 0.53/Ga/sub 0.47/As-In/sub 0.52/Al/sub 0.48/As avalanche photodiode array
Zheng X.G. Hsu J.S. Sun X. Hurst J.B. Li X. Wang S. Holmes A.L.Jr. Campbell J.C. Huntington A.S. Coldren L.A. 《Quantum Electronics, IEEE Journal of》2002,38(11):1536-1540
We report a 12 /spl times/ 12 In/sub 0.53/Ga/sub 0.47/As-In/sub 0.52/Al/sub 0.48/As avalanche photodiode (APD) array. The mean breakdown voltage of the APD was 57.9 V and the standard deviation was less than 0.1 V. The mean dark current was /spl sim/2 and /spl sim/300 nA, and the standard deviation was /spl sim/0.19 and /spl sim/60 nA at unity gain (V/sub bias/ = 13.5 V) and at 90% of the breakdown voltage, respectively. External quantum efficiency was above 40% in the wavelength range from 1.0 to 1.6 /spl mu/m. It was /spl sim/57% and /spl sim/45% at 1.3 and 1.55 /spl mu/m, respectively. A bandwidth of 13 GHz was achieved at low gain. 相似文献
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S. Privitera F. Wang P. Dumont-Girard K. Liu C. Bongiorno 《Microelectronic Engineering》2010,87(3):430-433
SixCryCzBv thin films with several compositions have been studied for integration of high precision resistors in 0.8 μm BICMOS technology. These resistors, integrated in the back-end of line, have the advantage to provide high level of integration and attractive electrical behavior in temperature, for analog devices. The film morphology and the structure have been investigated through transmission electron microscopy analysis and have been then related to the electrical properties on the base of the percolation theory. According to this theory, and in agreement with experimental results, negative thermal coefficient of resistance (TCR) has been obtained for samples with low Cr content, corresponding to a crystalline volume fraction below the percolation threshold.Samples with higher Cr content exhibit, instead, a variation of the TCR as a function of film thickness: negative TCR values are obtained for thickness lower than 5 nm, corresponding to a crystalline volume fraction below the percolation threshold; positive TCR are obtained for larger thickness, indicating the establishment of a continuous conductive path between the Cr rich grains. This property seems to be determinant in order to assure the possibility to obtain thin film resistors almost independent on the temperature. 相似文献
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Jie Liu Yugang Zhou Rongming Chu Yong Cai Chen K.J. Lau K.M. 《Electron Device Letters, IEEE》2005,26(3):145-147
We report an Al/sub 0.3/Ga/sub 0.7/N-Al/sub 0.05/Ga/sub 0.95/N-GaN composite-channel HEMT with enhanced linearity. By engineering the channel region, i.e., inserting a 6-nm-thick AlGaN layer with 5% Al composition in the channel region, a composite-channel HEMT was demonstrated. Transconductance and cutoff frequencies of a 1 /spl times/100 /spl mu/m HEMT are kept near their peak values throughout the low- and high-current operating levels, a desirable feature for linear power amplifiers. The composite-channel HEMT exhibits a peak transconductance of 150 mS/mm, a peak current gain cutoff frequency (f/sub T/) of 12 GHz and a peak power gain cutoff frequency (f/sub max/) of 30 GHz. For devices grown on sapphire substrate, maximum power density of 3.38 W/mm, power-added efficiency of 45% are obtained at 2 GHz. The output third-order intercept point (OIP3) is 33.2 dBm from two-tone measurement at 2 GHz. 相似文献
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Yi-Jen Chan Ming-Ta Yang 《Electron Devices, IEEE Transactions on》1995,42(10):1745-1749
The properties of both lattice-matched and strained doped-channel field-effect transistors (DCFET's) have been investigated in AlGaAs/In/sub x/Ga/sub 1-x/As (0/spl les/x/spl les/0.25) heterostructures with various indium mole fractions. Through electrical characterization of grown layers in conjunction with the dc and microwave device characteristics, we observed that the introduction of a 150-/spl Aring/ thick strained In/sub 0.15/Ga/sub 0.85/As channel can enhance device performance, compared to the lattice-matched one. However, a degradation of device performance was observed for larger indium mole fractions, up to x=0.25, which is associated with strain relaxation in this highly strained channel. DCFET's also preserved a more reliable performance after biased-stress testings.<> 相似文献
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Patrick W. C. Ho Firas Odai Hatem Haider Abbas F. Almuri T. Nandha Kumar 《半导体学报》2016,37(6):064001-13
Nonvolatile memories have emerged in recent years and have become a leading candidate towards replacing dynamic and static random-access memory devices. In this article, the performances of TiO2 and TaO2 nonvolatile memristive devices were compared and the factors that make TaO2 memristive devices better than TiO2 memristive devices were studied. TaO2 memristive devices have shown better endurance performances (108 times more switching cycles) and faster switching speed (5 times) than TiO2 memristive devices. Electroforming of TaO2 memristive devices requires~4.5 times less energy than TiO2 memristive devices of a similar size. The retention period of TaO2 memristive devices is expected to exceed 10 years with sufficient experimental evidence. In addition to comparing device performances, this article also explains the differences in physical device structure, switching mechanism, and resistance switching performances of TiO2 and TaO2 memristive devices. This article summarizes the reasons that give TaO2 memristive devices the advantage over TiO2 memristive devices, in terms of electroformation, switching speed, and endurance. 相似文献
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Zhiqun Cheng Jie Liu Yugang Zhou Yong Cai Chen K.J. Lau K.M. 《Electron Device Letters, IEEE》2005,26(8):521-523
We report broadband microwave noise characteristics of a high-linearity composite-channel HEMT (CC-HEMT). Owing to the novel composite-channel design, the CC-HEMT exhibits high gain and high linearity such as an output third-order intercept point (OIP3) of 33.2 dBm at 2 GHz. The CC-HEMT also exhibits excellent microwave noise performance. For 1-/spl mu/m gate-length devices, a minimum noise figure (NF/sub min/) of 0.7 dB and an associated gain (G/sub a/) of 19 dB were observed at 1 GHz, and an (NF/sub mi/) of 3.3 dB and a G/sub a/ of 10.8 dB were observed at 10 GHz. The dependence of the noise characteristics on the physical design parameters, such as the gate-source and gate-drain spacing, is also presented. 相似文献